异常！修改后代码如果是m4a程序会生成两个文件，分别是m4a和MP3，要求只输出MP3

要求只输出MP3文件，你可以在转换为MP3格式后删除原始的m4a文件。以下是修改后的代码：

import re
import tkinter
import requests
import threading
import tqdm as tt
from pydub import AudioSegment
import os

root = tkinter.Tk()
root.title('在线视频解析')
root.geometry('500x590+550+350')
headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/115.0'}
ac = tkinter.Listbox(root, width=50, height=20, font=('黑体', 12))
ac.grid(row=2, columnspan=10, sticky="n" + "s" + "w" + "e")


def sousuo():
    i = b1.get()
    ac.delete(0, 'end')

    def extract_music_info(content):
        p = '<em>|</em>'
        content = re.sub(p, '', content, flags=re.S)
        pattern = re.compile('subject.*?href="(.*?)">(.*?)</a>', flags=re.S)
        return pattern.findall(content)

    def search_music():
        url = 'https://www.hifini.com/search-' + i + '-1.htm'
        response = requests.get(url=url, headers=headers)
        return response.text

    def update_listbox(music_list):
        for music in music_list:
            pppp = music[1] + ":" + music[0]
            ac.insert('end', pppp)

    content = search_music()
    music_list = extract_music_info(content)
    update_listbox(music_list)


def xiazzi():
    def download_music():
        ppp = ac.get(ac.curselection())
        pp = re.search('thread.*?htm', ppp)
        v = pp.group()
        url1 = 'https://www.hifini.com/' + v
        response = requests.get(url=url1, headers=headers)
        ppp = response.text
        l2 = re.search('<script>.*?title:..(.*?).,.*?author:.(.*?).,.*?url:..(.*?).,', ppp, flags=re.S)
        p = 'https://www.hifini.com/' + l2.group(3)
        response = requests.get(url=p, headers=headers, stream=True)  # 设置 stream=True 以启用流式下载
        total_size = int(response.headers.get('Content-Length'))
        music_name = '{}-{}.m4a'.format(l2.group(2), l2.group(1))
        progress_bar = tt.tqdm(total=total_size, unit='B', unit_scale=True)  # 创建进度条
        with open(music_name, 'wb') as f:
            for data in response.iter_content(chunk_size=1024):
                progress_bar.update(len(data))  # 更新进度条
                f.write(data)
        progress_bar.close()  # 关闭进度条

        if music_name.endswith('.m4a'):
            mp3_name = music_name[:-4] + '.mp3'
            audio = AudioSegment.from_file(music_name, format='m4a')
            audio.export(mp3_name, format='mp3')
            print(mp3_name)
            os.remove(music_name)
        else:
            print(music_name)

    threading.Thread(target=download_music).start()


a1 = tkinter.Label(root, text='音乐下载器', anchor="center", font=('黑体', 24))
a1.grid(row=0, columnspan=10, sticky="n" + "s" + "w" + "e")
b1 = tkinter.Entry(root, width=35, font=('黑体', 16), )
b1.grid(row=1, column=3, padx=15)
search_button = tkinter.Button(root, text='搜索', command=sousuo)
search_button.grid(row=1, column=4)
download_button = tkinter.Button(root, text='下载', command=xiazzi)
download_button.grid(row=3, column=4)
root.mainloop()

这样，当下载的文件是m4a格式时，会自动将其转换为MP3格式，并在控制台上输出转换后的文件名。下载完成后，会删除原始的m4a文件。